An exploratory longitudinal investigation is proposed for the purpose of studying the effects of the social support of peer relations on emotional development during early adolescence. Several theoretical perspectives converge on the propositions that (1) the nature of a child's peer experiences during early adolescence is related to the child's ability to deal with the stresses of this period; and (2) peer relations are an important determinant of self-concept during early adolescence. Previous studies of these issues have been constrained by (1) their consideration of only the quantitative aspects of peer relations (i.e., popularity) without simultaneously considering the quality of an individual's specific friendship relations; and (2) by the use of one-time-only research designs that prevent the examination of the affects of relations on self-concept and emotional development over time. In the study described here, early adolescents will be followed as they make the transition from elementary to middle school. This transition has been previously identified as having a disruptive affect on peer relations and consequently it provides a unique setting for the study of the effects of a stressful event on the self-concept of persons in this age group. In this study, it will be possible to identify the differential effects of this transition on children whose friendships were consistent or inconsistent during this period. The use of appropriate multivariate statistical techniques (e.g., LISREL) will permit the identification of proposed "causal" relations between indices of peer relations, including both quantitative and qualitative aspects, and the processes of emotional development during early adolescence. This study is regarded as exploratory and unique because of its attempt to measure the multiple aspects of peer relations and because of its use of a longitudinal design with multivariate data analysis techniques. Moreover, it will permit a greater understanding of self-esteem and the processes underlying its acquisition during a time of the life cycle when issues related to "self" and identity become increasingly important developmental constructs. Funds are requested to support this research.